Area Forecast Discussion
Issued by NWS Knoxville/Tri Cities, TN

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000 FXUS64 KMRX 280721 AFDMRX Area Forecast Discussion National Weather Service Morristown TN 321 AM EDT Fri Apr 28 2017 .SHORT TERM (Today and Tonight)...
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The surface boundary has become stationary across the area as the upper level flow is generally parallel to the front. Rainfall throughout the day yesterday coupled with clearing skies and light wind is leading to fog this morning. The main locations impacted are along the TN/NC line and in SW VA. Observations have been below a mile at most of these locations. For now, it is patchy enough to continue without an advisory but will monitor conditions and will issue an advisory if it becomes necessary. The stationary boundary will lift to the north as a warm front today as an upper level ridge takes hold along the Atlantic Seaboard. Temperatures will run around 5-10 degree warmer than yesterday with the higher heights aloft and decent mixing. The main challenge for the forecast today will be with the PoPs. Model soundings indicate a strong capping inversion around 750-800 mb. The mid and upper level lapse rates are actually quite impressive. A few of the Hi-Res models indicate isolated shower/storms and have kept slight chance PoPs this afternoon for the western half of the area. Could see a stronger storm or two if this happens but forecasting that the cap should hold with most locations remaining dry. High temperatures today will top out well above normal in the 80s across most locations. .LONG TERM (Saturday through Thursday)... Strong high pressure will dominate area weather through the weekend. Saturday will be an especially hot day with temperatures reaching into the upper 80s and low 90s across most valley locations. The upper ridge shifts a bit eastward on Sunday and temperatures should be slightly cooler with highs generally reaching the mid 80s across the Tn Valley. With the strong daytime heating...diurnal convection will be possible... though this activity should be mainly confined to higher elevations. The first system of the extended will be a cold front moving in Sunday night into Monday...bringing showers and thunderstorms to the region. A strong 850MB jet accompanying the front could allow for a stray strong storm. Will briefly be between systems on Tuesday. Model consistency and confidence diminishes late in the period but the next system is progged into the area around the Wednesday/Thursday time frame for another chance of shower and thunderstorm activity.
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&& .PRELIMINARY POINT TEMPS/POPS...
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Chattanooga Airport, TN 85 67 91 68 / 20 0 10 10 Knoxville McGhee Tyson Airport, TN 84 66 90 66 / 10 10 10 10 Oak Ridge, TN 86 66 90 66 / 10 10 10 10 Tri Cities Airport, TN 85 61 89 64 / 10 10 10 10
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&& .MRX WATCHES/WARNINGS/ADVISORIES... NC...None. TN...None. VA...None. && $$ MA/MJB

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